Scientists Find Blood Clue That May Predict Who Survives Common Cancer

Scientists have discovered alterations in white blood cells that may forecast how patients with melanoma, the most perilous form of skin cancer, react to treatment, a revelation that could enable physicians to determine which patients are likely to benefit from immunotherapy. The research, led by Lucy Booth, a PhD candidate at King's College London, involved 24 patients and suggests that studying these immune cells could provide vital insights into improving melanoma treatment.

B and T cells, two types of white blood cells, were identified as significant contributors to survival and treatment outcomes in melanoma patients, according to Booth. Characterizing these cells in the blood offers a less invasive approach compared to biopsies. For the first time, the study found unique immune characteristics in patients' blood that could serve as potential biomarkers for disease progression.

Melanoma is the fifth most common cancer in the U.K., and about 112,000 new cases are expected in the U.S. this year, according to the American Cancer Society. Although treatable when detected early, melanoma remains highly lethal once it advances. Current treatments include surgery, targeted drugs, and immunotherapy, which trains the body's immune system to target and eliminate cancer cells.

However, nearly half of patients do not benefit from immunotherapy, and some experience severe side effects. Until now, doctors lacked a reliable method to predict who will respond well to immunotherapy and who is at risk of harm.

The study analyzed B cells, which produce antibodies, and T cells, which directly destroy cancer cells, during treatment. Researchers found coordinated changes in these immune cells that correlated with patient outcomes. Patients whose B and T cells showed renewed activation and expansion within six weeks of immunotherapy generally had better results, including improved survival.

Conversely, patients with immature or poorly functioning B cells throughout treatment had worse outcomes. Patients with weaker immune cells capable of triggering anti-cancer responses before treatment also had poorer survival rates. Certain T cell subtypes were associated with treatment side effects. The researchers discovered substantial differences in immune cell levels among patients, which may explain why individuals respond differently to the same treatment.

The team examined blood samples from 24 patients with stage 2 to 4 melanoma, alongside samples from 25 healthy individuals, at various points before and during treatment. Using mass cytometry, a technique allowing scientists to analyze multiple characteristics of individual immune cells simultaneously, researchers detected rare cell populations and tracked their evolution over time.

This study marks the first time circulating B and T cells were examined in such detail in melanoma patients' blood. The findings aim to integrate blood immune profiling into clinical settings to guide surveillance and early intervention for melanoma patients.